This invention relates to saws for cutting grooves or the like in the surface of concrete slabs, particularly cured concrete slabs, such as in the top surface of the concrete floor of a building or the like.
Concrete floors, commercial-sized vehicle garage floor surfaces, for example, and the like are commonly poured in slabs, a slab being a substantially planar expanse of concrete of a given thickness, commonly less than eight inches, whose side dimensions are commonly defined through the use of rigid forms that are removed after the concrete has cured sufficiently. In certain concrete slab pouring operations, the concrete is sufficiently self-supporting as poured so that a xe2x80x9cmovingxe2x80x9d form may be employed, thereby speeding up the overall process.
Expansion joints are commonly deployed between adjacent sides of adjacent slabs to accommodate expansion of the concrete in response to climatic conditions and other external influences. These expansion joints are not to be confused with the stress-relieving relatively narrow slits which are cut in uncured concrete employing a single-bladed implement, and which are materially less demanding of the implement than the demands placed on implements employing in cutting cured concrete.
Expansion joints between the adjacent sides of adjacent slabs of concrete, on the other hand, are robust and commonly require the insertion of a resilient strip of polymeric material into the space between the adjacent sides of the slabs. In a common form, the compressible strip takes the form of a generally T-shaped cross-section strip in which the leg of the xe2x80x9cTxe2x80x9d resides within a space between the adjacent sides of the slabs and each of the side wings of the xe2x80x9cTxe2x80x9d lays in a groove of generally rectangular cross-section that is cut along the respective side margin of each of the adjacent slabs. Such groves are referred to as xe2x80x9cblock-outsxe2x80x9d. The wings are thereafter anchored in place employing a polymeric material that bonds the wings in their respective grooves. Proper installation and functioning of such expansion joints requires that the groove along the side of a slab be of a precise depth, commonly xc2xe inch. To accommodate a wing of the expansion joint, each groove commonly must be between about 4 and about 8 inches in width.
When employing either rigid forms or a xe2x80x9cmovingxe2x80x9d form in the pouring of a concrete slab, it is impractical, or even impossible to form the required groove along the side edges of a slab for receipt of the wings of the expansion joint. Thus, the grooves must be cut into the slab after the concrete has cured.
Heretofore, it has been common practice to employ a single-bladed self-propelled concrete saw or a multi-bladed hand-held saw for cutting the aforesaid side margin grooves in cured concrete slabs. The blades of these saws are limited to cutting a kerf which is relatively small in width, usually between about xe2x85x9 and about xe2x85x9c inch in width, due to the cost of manufacture of wider blades. Thus, it is common practice in the art to perform a plurality of parallel spaced-apart cuts along the desired length of the groove, employing a single circular rotating blade, such cuts being spaced apart by about one inch, and thereafter breaking away the uncut concrete between the parallel cuts, as by means of a hammer, or other like instrument or device. Use of a single bladed saw for cutting wide grooves is inordinately time-consuming in that multiple passes of the saw blade along the length of the groove must be employed to achieve the desired width of the groove. Moreover maintaining parallelism of the several cuts requires some form of guidance of the saw with reference to the side edge of the slab, for example. Known multi-bladed concrete saws are limited to hand-held devices which are restricted in their maximum depth of cut, speed of cutting, and overall efficiency. These devices are suitable for cutting grooves of limited length, such as grooves in stair steps and the like. However, due to their relative fragile construction, which is required to permit them to be hand-held, these devices are not suitable for cutting grooves of extended length such as in concrete slabs or the like. All known self-propelled concrete saws, aside from the massive highway surface groove-cutting machines which are unsuitable in size and mobility for use in cutting block-outs or troughs in concrete slabs, employ only a single blade.
It is therefore an object of the present invention to provide a mobile cured-concrete-cutting saw suitable for performing block-outs and troughs in the top surface of a concrete slab.
It is another object of the present invention to provide a mobile cured-concrete-cutting saw which is portable for ready transport to and from work sites within buildings.
It is another object of the present invention to provide a self-propelled cured-concrete-cutting saw equipped with a plurality of circular cutting blades mounted for simultaneous operation thereof.
It is another object of the present invention to provide a cured-concrete-cutting saw having a blade assembly including a plurality of cutting blades and wherein the blade assembly is selectively adjustable to different cutting depths.
It is another object of the present invention to provide a cured-concrete-cutting saw which is suitable for the cutting of a block-out or trough of non-rectangular cross-section in a concrete slab.
Other objects and advantages of the present invention will be recognized from the description contained herein, including the claims and the drawings.